This invention relates to a motion simulator, and particularly an improved motion simulator in which occurrence of undesired moving sensations are eliminated during the creation of moving sensations using gravity and thereby creation of a moving sensation which is more similar to the actual situation is possible.
Generally, a motion simulator refers to a device which simulates motions of objects such as an airplane or an automobile and allows people to feel moving sensations within a limited space.
As a general motion simulator such as the above, a 6 DOF (degree of freedom) motion simulator (100) in which a movable frame (120) is driven by six actuators (131, 132, 133, 134, 135, 136) is depicted in FIGS. 1 to 3b. 
As depicted in FIG. 1, the conventional 6 DOF motion simulator(100) has a structure which includes a stationary frame (110), a movable frame (120), and a plurality of actuators (131, 132, 133, 134, 135, 136).
Said stationary frame (110) is installed fixedly against the ground (gravity field). Said movable frame (120) is disposed above the gravitational direction of the stationary frame (110). A passenger compartment (140) is disposed on the top surface of said movable frame (120).
Said plurality of actuators (131, 132, 133, 134, 135, 136) are disposed between the stationary frame (110) and the movable frame (120). Electric, hydraulic, or pneumatic actuators are generally used for each of said actuators.
Said each actuator (133, 132, 133, 134, 135, 136) is rotatably connected at both ends thereof by respective pairs of universal joints (131a and 131b, 132a and 132b, 133a and 133b, 134a and 134b, 135a and 135b, 136a and 136b).
The conventional 6 DOF motion simulator (100) configured as the above allows the passenger (170) in the passenger compartment (140) to feel moving sensations similar to those felt when actually riding an airplane or automobile by driving the plurality of actuators (131, 132, 133, 134, 135, 136) and thereby moving the movable frame (120).
For instance, for a racing car that has suddenly taken off and continues to accelerate, the passenger feels sensations of being pulled backward due to acceleration, and this sensation is continued while acceleration after start is being progressed.
To create such sensation, the motion simulator (100) drives the plurality of actuators (131, 132, 133, 134, 135, 136) and firstly accelerates the movable frame (120) forward, as depicted in FIG. 2a. In the above case, the passenger (170) within the passenger compartment (140) feels a pulling sensation from the rear to the force of inertia.
However, because the range of motion of the motion simulator (100) has a limit, the movable frame (120) which has been accelerated and moved forward shortly falls within this limit. At this time, as depicted in FIG. 2b, when the front of the movable frame (120) is lifted, the passenger (170) continues to feel said sensation due to gravity.
On the other hand, as another example, for an automobile turning along a large curve, the passenger feels a pushing sensation to the outer direction of the curve due to centrifugal force, and continues to feel this sensation while the turning is being progressed.
To create such sensation, the motion simulator (100) actuates the plurality of actuators (131, 132, 133, 134, 135, 136) and firstly accelerates the movable frame (120) to the side director, as depicted in FIG. 3a. In the above case, the passenger (170) within the passenger compartment (140) feels a sensation of being pushed in the opposite direction of said movement due to the force of inertia.
However, also for this case, because the range of motion of the motion simulator (100) has a limit, the movable frame (120) which has been accelerated and moved to the side direction shortly falls within this limit. At this time, as depicted in FIG. 3b, when the side of the movement direction of the movable frame (120) is lifted, the passenger (170) continues to feed said sensation.
On the other hand, in FIGS. 4 to 6, as another example of the conventional motion simulator, a 3 DOF motion simulator (101) of which the movable frame (120) is driven by three actuators (131xe2x80x2, 132xe2x80x2, 133xe2x80x2) is depicted.
According to FIGS. 4 to 6, the configuration of the conventional 3 DOF motion simulator (101) is identical to that of the 6 DOF motion simulator except that the former has three actuators (131xe2x80x2, 132xe2x80x2, 133xe2x80x2 and that it is provided with a separate support member (150) to limit the occurrence of unintended forward/backward linear motion, left/right linear motion, and rotating motion centered on the top, bottom axes perpendicular to the surface of the movable frame (120).
Therefore, in describing the configuration of the 3 DOF motion simulator (101), same reference numbers are designated for parts identical to those of the 6 DOF motion simulator, and the descriptions thereof are omitted.
Meanwhile, as mentioned above, because all motions of the movable frame (120) can not be restrained with only the actuators (131xe2x80x2, 132xe2x80x2, 133xe2x80x2), in the depicted conventional 3 DOF motion simulator (101), there is provided a separate support member (150) for limiting the occurrence of unintended motion to the movable frame (120).
Said support member (150) is composed of a cylinder (151) which is fixed on the stationary frame (110), a piston (152) which moves up and down along said cylinder, and a universal joint (153) which connects said piston and the movable frame (120)
In the case of the conventional 3 DOF motion simulator (101) configured as the above, because there is no DOF to the horizontal direction, that is, the direction perpendicular to gravity, when creating continuous accelerating motion or rotating motion as mentioned above, only the force of gravity is used.
Namely, to create a linear accelerating sensation, the motion simulator (101) drives the plurality of actuators (131xe2x80x2, 132xe2x80x2, 133xe2x80x2) and lifts the front of the movable frame (120) and thereby allows the passenger (170) to feel a rearward pulling sensation, as depicted in FIG. 5.
In addition, to create rotating movement, the motion simulator (101) drives the plurality of actuators (131xe2x80x2, 132xe2x80x2, 133xe2x80x2) and lifts one side of the movable frame (120) and thereby allows the passenger (170) to feel a pushing sensation to the other side, as depicted in FIG. 5.
However, according to the conventional motion simulator (100, 101) configured as the above, both simulators have a structure in which the center of gravity of the passenger (170) is above the center of rotation of the movable frame (120).
Due to the above, when representing acceleration from continuous linear acceleration or from centrifugal motion to the side direction, that is, when the movable frame (120) is tilted to utilize gravity, there is the problem of occurrence of undesired acceleration.
This awkward sensation (that is, force) may be expressed with the following equation
Ap=Av+Axc3x97Rpv+xcfx89xc3x97xcfx89xc3x97Rpv
Wherein, Ap is the acceleration vector felt by the passenger of the motion simulator, Avis the acceleration vector of the moving movable frame of the motion simulator, A is rotational acceleration vector of the movable frame, Rpv is the relative position vector of the passenger on top of the motion plate, and xcfx89 is the rotational velocity vector.
The awkward sensation is sum of the calculation value of the cross product of A and Rpv vectors, which as Axc3x97Rpv, and the calculation value of the cross product of xcfx89, xcfx89, Rpv vectors, which is xcfx89xc3x97xcfx89xc3x97Rpv.
Namely, n the structure of conventional motion simulators (100, 101), because the center of gravity of the passenger (170) exists vertically above the center of rotation of the movable frame (120), when starting to rotate the movable frame to apply an accelerating sensation to the passenger, the value of the Axc3x97Rpv vector becomes the opposite direction of the acceleration intended to be created.
A graph displaying the above is shown in FIG. 7. The dotted line in FIG. 7 represents the control reference signals which repeats acceleration and deceleration of 3 m/s2, and the solid line represents the ac/deceleration sensed by the passenger riding on the motion simulator driven by inputting the above signals.
In FIG. 7, as shown by the pointed portions bulging out in the opposite direction of the changes in the reference signals, in contrary to the intended pushing to one side sensation, a sudden attraction to the opposite side is experienced.
As a result of such problems, as shown by the solid line of FIG. 7, a moving sensation in the opposite direction of the moving sensation intended to be created (dotted line of FIG. 7) is applied, and furthermore, the time taken to track the intended moving sensation is delayed. This means a decline in actuality experienced by the passenger.
In the case of the 6 DOF motion simulator taken for instance previously, because of the limited range of linear motion, if the movable frame is rotated, a moving sensation opposing the intended moving sensation occurs as soon as the rotation is initiated.
In the foregoing, the problems of the conventional motion simulator has been described taking the 6 DOF and the 3 DOF motion simulators as two types of examples. However, although the extent may vary, the above mentioned problems of conventional motion simulators occur in all motion simulators having different degrees of freedom that possess functions which apply linear accelerating sensations to passengers using rotation and gravitational acceleration, and whose centers of rotation are located beneath the passenger.
Therefore, the technical task that the present invention seeks to achieve, that is, the object of the present invention is to resolve he above mentioned problems of the conventional motion simulator by providing a motion simulator that allows moving sensations similar to she intended sensations and which reduces tracking time, through the elimination of undesired moving sensations when creating moving sensations using gravity.
The above object of this invention is achieved by providing a motion simulator according to his invention characterized in that it comprises a stationary frame; a movable frame which is disposed beneath said stationary frame in the direction of gravity, and which has the passenger compartment attached on the bottom surface thereof; and a driving device disposed between said stationary frame and said movable frame, which rotationally or linearly moves the movable frame.
According to the motion simulator of this invention, because the movable frame is disposed underneath the stationary frame, the center of gravity of the passenger is lower than the center of rotation of the movable frame.
Namely, because the value of the Axc3x97Rpv vector is in the same direction as the acceleration intended to be created even at he point of rotation commencement, there are advantages in which undesired accelerating sensations are not occurred even during acceleration representation using gravity, and the tracking time of the intended moving sensation is reduced.